Gas turbocompressor plant



Patented Oct. 7, 1941 GAS TURBOCOMPRESSOR PLANT Claude Seippel,Ennetbaden, Switzerland, assignor to Aktiengesellschaft Brown, Boveri &Cie,

Baden, Switzerland Application August 17, 1938, Serial No. 225,408 InGermany August 23, 1937 (Cl. 60--4l) 4 Claims.

The present invention relates to gas turbocompressor plants, moreparticularly to plants in which the pressure of the medium compressed ina multistage compressor isat least equal to the pressure of theoperating gas entering a multistage turbine and in which the pressure atindividual stages of the compressor is maintained equal or inpredetermined proportion to the pressure at individual stages of the gasturbine. I A plant according to the present invention may be used forproducing mechanical and/or electric power or it may be used forcompressing air for charging internal combustion engines or forcompressing air or gases for operating high pressure combustion chambersor reaction chambers for carrying out chemical processes. Plants of thistype comprise a gas turbine and a compressor connected to and operatedby said turbine. The medium compressed in the compressor is used eitherdirectly for operating the gas turbine or is first used for producingpower, for example, in an internal combustion engine, and/or forcarrying out a heating, combustion or chemical proc ess. Usuallyconsiderable pressures must be produced in the compressor such as 15lbs. per sq. inch to 45 lbs. per sq. inch or even more; the gas turbineis also required to operate at considerable pressure. Since usually alsolarge amounts of medium must be compressed, compressors of themultistage rotary typemust 'be used. v

In plants in which turbine and compressor are mechanicallyinterconnected and also for compressed medium and gas flow, i. e. wherethe medium compressed in the compressor is used directly or indirectlyfor operating the gas turbine satisfactory cooperation of turbine andCc.npressor is always possible at a certain output and pressure and/ortemperature of the operating media and a certain speed of the turbineand compressor. Cooperation, however, is difficult and at reducedefficiency when one or more of these operating characteristics is or arechanged as, for example, at partial load operation.

It is an object of the present invention to provide agas-turbo-compressor plant of the type specified in which satisfactorycooperation at highest efficiency of turbine and compressor is assuredat all operating conditions by the application of simple and inexpensivemeans. According to the present invention the gas turbine as well as thecompressor are each provided with one or more leak oifs. The leak offsof the compressor are individually connected by means of equalizingconduits with individual leak offs of the turbine where the pressure atnormal operating conditions is equal or lower. This arrangement in manycases yields the desired result without additional control means.Throttling means and/or reducing valves may be provided in saidequalizing conduits for further improvement.

' Further and other objects of the present invention will be hereinafterset forth in the accompanying specification and shown in the drawingwhich, by way of illustration, shows what I now consider to be apreferred embodiment of my invention.

In the drawing:

Figure l is a diagrammatic part cross sectional layout of a plantaccording to the present invention.

Figure 2 is a diagram illustrating relative pressure conditions in thecompressor.

Figure 3 is a diagram illustrating relative pressure conditions in thegas turbine.

Referring more particularly to Fig. 1 of the drawing, 1 designates thecompressor having an intake 2 and a discharge side 3. 4 designates thegas turbine having a gas inlet 5 and a gas outlet 6. l designates theblading of the compressor and B that of the gas turbine. 9 and ID areleak oiTs of the compressor which are individuallyv connected with theleak offs 4 and I3 Of the gas turbine respectively by means of conduitsH and I2. The leak offs are provided at such pressure stages of thecompressor and turbine that, at'

tions the gas pressure falls on its path from inlet 5 to outlet 6 asindicated by the solid line in Fig. 3.

The solid lines in Figures 2 and 3 do not show the absolute existingpressures but indicate only the relative pressure conditions. Theinclination of the lines gives a picture of the relative pressure andexpansion conditions in bladings I and 8.

If for any reason the pressure conditions at one point of the plant arechanged, for example reduced because the resistance between compressorand gas turbine is reduced or the load on the plant is reduced, therelative pressure conditions in the compressor do not follow the line20--2 l- 22 but the dotted line 20-2622, i. e. the first stages of thecompressor produce a relatively higher pressure and the high pressurestages produce relatively less pressure. The result is a reduction ofefiiciency of the compressor. In the gas turbine opposite conditions areobtained: expansion is most marked in the high pressure stages whereasthe low pressure stages do little or EL: '1. ion does not follow the-..o but the dotted line 23-2'l-- in Fig. 3. The velocity of the mediumflowing through the turbine buckets is not that for which the bucketsare designed.

If, according to the invention, one or more stages of the compressor aredirectly connected with one or more stages of the turbine the pressureis equalized and the operation takes place at better emciency. Since thepressure in the compressor rises from point 2| to point 26 and in theturbine is reduced from point 24 to 21 compressed medium flows in aconduit connecting the compressor stage corresponding to point II, 26and the turbine stage corresponding to point 24, 21 from the compressorinto the turbine. The volume of medium flowing through the first stagesof the compressor is thereby increased and the relative pressuredecreased, the compressor buckets are filled and its efficiency isincreased. The medium flowing from the compressor through the equalizingconduit into the gas turbine causes an increase of pressure in theturbine and a reduction of expansion in its high pressure and increaseof expansion in its low pressure stages, whereby normal and highefficiency operating conditions are restored.

In most cases the equalization takes place automatically and if thecross sectional areas of the equalizing conduit are correctlydimensioned no further regulating devices are needed. In order to beable to adapt the installation to varying conditions throttlingorifices, valves l5, l6 and/or check valves I8, 19 may be provided. Bysuitable operation of control means and/or itthe conditions in theequalizing conduits can be adjusted to produce best equalizingconditions.

The medium discharged, thro'iigh outlet 3 may be used for charging thecombustion chamber of an internal combustion motor, a combustion chambersuch as is shown in the patent to W. G. Noack No. 1,948,539, or forserving a chemical process in a reaction chamber such as is shown inPatent No. 2,227,666, issued January 7, 1941, to W. G. Noack, and incopending application of W. G. Noack, Serial No. 209,906, filed May 25,1938, a combustion chamber 28 being indicated in Fig. 1. The combustiongas produced in and discharged from said combustion chamber is used foroperating turbine 4.

For starting up the plant, for quick acceleration or slowing up atchanging operating conditions and for making up differences in theoutput of the turbine and load requirements of the compressor anauxiliary motor [1 may be provided. If the plant is uscd for theproduction of power, i? may be the main electric generator. In a plantin which the medium compressed in compressor l is used for the operationof a high pressure combustion chamber or chemical reaction chamber 28and in which plant the turbine 4 is operated by the high pressureexhaust gases from chamber 28, the machine 2'! may operate at times asmotor and at other times as generator. If 28 is an internal combustionmotor which can be started and operated by itself motor H may beomitted.

While I believe the above described embodiments of my invention to bepreferred embodiments, 1 wish it to be understood that I do not desireto be limited to the exact details of design and construction shown anddescribed, for obvious modifications will occur to a person skilled inthe art.

I claim:

1. A heat power plant comprising a multistage gas turbine, a multistagerotary compressor driven by said turbine, a high pressure combustionchamber comprising fuel supply means and being connected for compressedair flow with said compressor and being supplied with combustion airtherefrom and being connected for combustion gas flow with and supplyingcombustion gas to said turbine for its operation, and a. pressureequalizing conduit directly interconnecting such an intermediate stageof said compressor and such an intermediate stage or said turbine thatair flows throughsaid conduit from said compressor directly to saidturbine in an amount decreasing at increasing total flow of air throughsaid compressor and that there is no air flow through said equalizingconduit at full load operation of said plant.

2. A heat power plant comprising a multistage gas turbine, a multistagerotary compressor driven by said turbine, a high pressure combustionchamber comprising fuel supply means and being connected for compressedair flow with said compressor and being supplied with combustion airtherefrom, and being connected for combustion gas flow with andsupplying combustion gas to said turbine for its operation, and aplurality of equalizing conduits individually directly interconnectingsuch individual intermediate stages of said compressor and suchindividual intermediate stages of said turbine that air flows throughsaid conduits from said compressor directly to said turbine in an amountdecreasing at increasing total flow of air through said compressor andthat no air flows through said equalizing conduits at full loadoperation of said plant.

3. A heat power plant comprising a multistage gas turbine, a multistagerotary compressor driven by said turbine, an exhaust conduit connectedwith said compressor, a high pressure combustion chamber comprising fuelsupply means and being connected with said exhaust conduit and suppliedwith combustion air from said compressor, and being connected forcombustion gas flow with and supplying combustion gas to said turbinefor its operation, and a pressure equalizing conduit of substantiallysmaller flow capacity than that of said exhaust conduit and directlyinterconnecting such an intermediate stage of said compressor and suchan intermediate stage of said turbine that air flows through saidconduit from said compressor directly to said turbine in an amountdecreasing at increasing total flow of air through said compressor.

4. A heat power plant comprising a multistage gas turbine, a multistagerotary compressor driven by said turbine, a high pressure combus tionchamber comprising fuel supply means and being connected for compressedair flow with and being supplied with combustion air from saidcompressor, and being connected for combustion gas flow with andsupplying combustion gas to said turbine for its operation, anequalizing conduit directly interconnecting such an intermediate stageof said compressor and such an intermediate stage of said turbine thatair flows through said conduit from said compressor directly to saidturbine in an amount decreasing at increasing total flow of air throughsaid compressor, and an air flow control means in said equalizingconduit.

CLAUDE SEIPPEL.

